Seven years ago at least one third of the junk mail in Seattle was pre-sorted off site by private companies, which were mostly owned and staffed by Asian immigrants.
The junk mail arrived at the main USPS facility near the airport, packed in official USPS trays, and perfectly sorted for each delivery route.
“The junk mail arrived at the main USPS facility near the airport, packed in official USPS trays, and perfectly sorted for each delivery route.”
Thats very common. The rate for pre-sorted junk mail is much better than for unsorted. Anyone who does mail marketing knows this.